US 20080058912 A1
An electrode array has a flexible body supporting a plurality of electrodes. Each electrode comprises an exposed connector pad at the upper end of the body, an exposed recording/stimulating pad at the lower end of the body, and a conductor located within the body and electrically connecting the connector pad and the recording/stimulating pad. In one embodiment the electrode array has an elongated recording/stimulating portion coiled or folded to distribute the exposed recording/stimulating pads in three dimensions. An implantation method employs an introducer with a helical portion to which an end of the flexible electrode is attached. The helical portion straightens to pass through a small-diameter cannula and then resumes its helical configuration to place the recording/stimulating portion of the attached electrode in a helix within the patient's tissues.
1. An apparatus comprising:
an introducer having an upper portion, a lower helical portion, and a distal tip; and
a flexible electrode having a connector area adjacent its upper end, an electrode recording/stimulating section adjacent its lower end, and a signal conducting region in its intermediate portion electrically interconnecting the connector area and the electrode recording/stimulating section;
said lower end of said electrode being attached to said lower portion of said introducer;
whereby rotation of said introducer rotates said flexible electrode.
2. The apparatus of
3. The apparatus of
4. The apparatus of
5. The apparatus of
6. The apparatus of
7. The apparatus of
8. An apparatus comprising:
a substantially planar electrode body,
an electrode comprising an electrode pad at a lower end, a connector pad at an upper end, and a conductor electrically connecting said electrode pad and said connector pad;
said conductor being enclosed within said body;
a first opening in said body in registry with said electrode pad so as to expose said electrode pad to the ambient; and
a second opening in said body in registry with said connector pad so as to expose said connector pad to the ambient.
9. The apparatus of
10. The apparatus of
11. The apparatus of
12. The apparatus of
13. The apparatus of
wherein said body comprises a first elongated segment and a second elongated segment extending laterally from a lower portion of said first elongated segment; and
wherein said electrode pads are elongated and extend along said second elongated segment.
14. The apparatus of
15. The apparatus of
16. The apparatus of
an electrode comprising a second electrode pad at a lower end, a second connector pad at an upper end, and a second conductor electrically connecting said second electrode pad and said second connector pad.
17. The electrode of
18. A method of introducing a portion of an electrode into the tissues of a patient, comprising:
providing an introducer having a proximal portion, a distal end, and a distal helical portion;
providing a flexible electrode having a proximal portion and a distal portion, said distal portion of said electrode being attached to said distal end of said introducer;
providing a cannula having an inner diameter smaller than the diameter of said helical portion of said introducer;
inserting a distal end of said cannula into the tissues of a patient and advancing said cannula until said distal end of said cannula is located proximate to a target site;
inserting the lower end of said introducer into the proximal end of said cannula; and
rotating said introducer in the direction of the helix of the distal portion of said introducer and advancing said introducer such that said distal helical portion of said introducer unwinds to pass through said cannula and resumes its helical configuration when it exits the distal end of said cannula;
decoupling said introducer from said flexible electrode; and
rotating said introducer in the direction opposite to the helix of the distal portion of said introducer and withdrawing said introducer such that said distal helical portion of said introducer unwinds to pass through said cannula, leaving said distal helical portion of said flexible electrode implanted in the tissues of said patient.
19. The method of
20. The method of
wherein said flexible electrode is adhesively bonded to said introducer by an adhesive that dissolves when exposed to fluid within the tissues of the patient, and
wherein said step of decoupling said introducer from said flexible electrode comprises the step of allowing said adhesive to be dissolved by fluid within the tissues of the patient.
This invention relates generally to electrodes for use within the body of a patient and to systems of manufacturing and of implanting such electrodes. More specifically, the invention relates to a flexible electrode that can create a distribution of electrode sites within the interior bulk of a tissue using only one penetration along a single electrode track.
When used in medical applications, an electrode is an electrically conductive structure that either electrically stimulates or records the electrical activity of surrounding tissue within the body of a patient. Examples of medical applications for electrodes include deep brain stimulation and brain mapping. Deep brain stimulation electrodes have applications in the treatment of Parkinson's, epilepsy, chronic pain, depression, muscle spasticity, schizophrenia, anxiety, coma, addition, migraine, and Alzheimer's, among others.
Conventional medical electrodes present a number of disadvantages. First, known medical electrode arrays cannot be inserted into tissue without causing trauma to the tissue, a characteristic that is especially disadvantageous in the case of deep brain stimulation and brain mapping electrodes. Consequently, known electrode arrays can only be placed on the surface of the brain, making it impossible to stimulate or detect electrical activity below the surface of the brain without causing trauma to delicate brain tissue.
Second, known medical electrodes are typically denser than the tissue into which they are positioned. Thus any sudden acceleration or deceleration can cause movement of the electrode relative to the tissue, resulting in shearing or abrading of the surrounding tissue.
Third, known medical electrodes are typically less compliant than the surrounding tissue. Thus any mechanical vibration that results from energy input into the body will cause relative motion between the electrode and the surrounding tissue, again with the attendant risk of shearing or abrasion of the surrounding tissue.
Electrodes made to have a high degree of compliance are known. A problem with such structures is that they are limited in the manner in which they can interact with a particular tissue. More specifically, such highly flexible electrodes cannot be inserted into tissue because the flexible electrode itself does not have the necessary mechanical stiffness for it to be pushed into the cellular matrix of a given tissue. These devices can only be affixed to the surfaces of a tissue or inserted into a bodily organ that has a hollow cavity, such as the surface of the cochlear membrane, which will allow insertion of the flexible structure.
In a first aspect, the present invention comprises an electrode array having a substantially planar electrode body supporting one or more electrodes. Each of the electrodes comprises an electrode pad at its lower end, a connector pad at its upper end, and a conductor located within the body and electrically connecting the electrode pad and the connector pad. The body has an opening in registry with the electrode pad to the ambient and an opening in registry with the connector pad so as to expose the pads to the ambient.
In another aspect the invention comprises an electrode and an introducer for implanting the recording/stimulating section of the electrode into the tissues of a patient. The introducer has a helical lower portion. The lower end of the electrode is attached to the distal end of the introducer.
In a further aspect of the invention, introducer is used to implant the recording/stimulating section of the electrode into the tissues of a patient. The distal end of a cannula is inserted into the tissues of the patient. The distal end of the introducer is introduced into the cannula. The helical portion of the introducer unwinds to pass through the cannula and reforms into a helix as it exits the lower end of the cannula. The introducer pulls the recording/stimulating section of the electrode along with it to position it in a helical configuration within the tissues of the patient. The introducer is then detached from the electrode and extracted, leaving the electrode in place.
Objects, features, and advantages of the present invention will become apparent upon reading the following specification, when taken in conjunction with the drawings and the appended claims.
Referring now to the drawings, in which like numerals indicate like elements throughout the several views,
With further reference to
For convenience of description the electrode array 10 depicted in the drawings shows only a single pair of electrodes 21. It will be understood that the number of electrodes 21 is not critical and that a greater or lesser number of electrodes can be provided, depending upon the needs of the particular application.
After a period of exposure to fluid within the tissues, the adhesive layer coupling the electrode array 10 to the introducer 32 dissolves. Then, as shown in
As with the electrode 10, the electrode 50 can also be defined in terms of its functionality, with a connector area 73 being located adjacent its upper end 60, an electrode recording/stimulating section 74 adjacent its lower end 58, and a signal conducting region 75 in its intermediate portion interconnecting the connector area 73 and the electrode recording/stimulating section 74.
As shown in
The purpose of coiling the electrode recording/stimulating section 74 of the electrode array 50 into a cylinder is to locate the electrodes in a three-dimensional arrangement, as opposed to the substantially linear arrangement of the electrode recording/stimulating section 24 of the electrode array 10. However, it will be appreciated that other methods of placing the electrode recording/stimulating section 24 of the electrode array 10 in a non-linear path may be implemented, such as folding the section 24 over onto itself a number of times to create a substantially box-shaped array 98 (see
Manufacture of the electrode array 10 will now be explained with reference to
Referring now to
Referring now to
Unless otherwise stated, terms used herein such as “top,” “bottom,” “upper,” “lower,” “left,” “right,” “front,” “back,” “proximal,” “distal,” and the like are used only for convenience of description and are not intended to limit the invention to any particular orientation.
Finally, it will be understood that the preferred embodiment has been disclosed by way of example, and that other modifications may occur to those skilled in the art without departing from the scope and spirit of the appended claims.